Gem grinding and polishing machine



A. BOERNER.

GEM GRINDING AND POLISHING MACHINE. APPLICATION mm SEPT. 1. I917.

1,331,480. Patented Feb. 24, 1920.

3 SHEETS-SHEET 1.

A. BOERNER.

GEM GRINDING AND POLISHING MACHINE.

APPLICATIONFILED SEPT. 7. l9l1. I

Patented Feb. 24,1920.

3 SHEETS-SHEET 2 \\llllll\\ v A @ozrruzr.

lrwenror.

H rrvr z A. BOERNER.

GEM GRINDING AND POLISHING MACHINE.

APPLICATION FILED SEPT. I. 1917.

1,331,486. Patented Feb. 24,1920.

3 SHEETS-SHEET 3.

A EJoerner.

InvQnror.

QrYorney.

STATES PATENT OFFICE.

l mNo BOEBNER, or scHEvENINGE NETHERLANDS.

To all whom it may concern:

Be it known that I,ARNo'B ERNER, having no nationality, residing at Scheveningen, State of the Netherlands, have invented certain new and useful Improvements in Gem Grinding and Polishing Machines, of WlllCll the following is aspecification.

. This invention relates to gem grinding and polishin machines, and more part cularly to mac lines to be used for grindmg and polishing diamonds.

The contrivance generally used for grind 'ing and polishing diamonds is called a mill and it comprises a lapping wheel, known in the trade as a skive, and rotating at high speed in a horizontal plane; the polisher is supplied with hand tools called tongs, which, as thename implies, is a too] for the purpose of firmly grasping a leaden dop in which the stone is, as it were, soldered in a proper position to ex- 5 l pose the proper surface whentouching the This known apparatus has obvious disadvantages. In the first place the dop as gen-- erally used cannot hold more than one stone; as this stone, every time when a facet has been completed by .a polisher, mustbe adjusted in the proper position for the neirt facet by another operative, called. turner, it is ,clear that the ,work of the polisher is repeatedly interrupted, which necessarily interferes with his capacity. Moreover, the

- said apparatus does not permit the polisher to work with more than four stones at one and the same time, as it would entail too great. risk to attempt to workwith more than four tongs on one skive, becauseshould the polisher go too deep on a facet he would be compelled to take more'than is required from some-of the others in order to e pensate his error, and this means a 10s of weight to the stones. In this connection" it ratus the progress of the, grinding 0 eration 1s not in any way limited by mec anical means, sothat'the polisher must. use

tongs from the skive to prevent o'vergrind:

ing.

Another objectionable feature of the known apparatus is that the polisher for positioning the stone on the lapping wheel Specification of Letters Patent. Patented Feb, 24, 192() v 4 Application filed September 7, 1917 Serial No. 190,137. 1 p

' almost entirely depends uponthe position in the above disadvantageous features may be' I entirely obviated by employing in combination with the ordinary lapping wheel a do adapted to hold a plurality of stones an provided with spherical bearing surfaces by means of which it is rotatably or adjustably mounted between spherical bearing recesses in a dop holder.

In a preferred form of execution the dopfree ends spherical bearing recesses to form bearings for the dop, means being provided for ad usting the d1stance between the said spherical recesses. The dopholder may be detachably secured to an arm, which is pivholder comprises two fingers having at their otally mounted on ahorizontal shaft outside the lapping wheel in sucha manner that it is movable in a radial plane with'regard to thesaid wheel. 'For limiting the extent .of vertical movement of the stone, z. e. the thickness that will be ground of, a

positive stop,- adapted to be raised or;

lowered by means of a' micrometer screw, may be providedin such a manner that the arm for supporting the dop holder, when in its polishing position, may be engaged thereby.

In order that the stone, after the grinding operation proper has been finished, may be polished, z. a lpcilprqrlzated acrossthe rotating jlapping w ee t e supportin the dopholder may be mounted in a slide adapted to be moved in a horizontal planeis to be noted that in the ordinary appain a radial direction with regard to the wheeL.

The dop according to the present inven tion requires a special"contrivance for-setting 't-he stones. This apparatus comprises a vessel containing a cooling liquid and provided witli' rneans for rotatably supportin the dop so that part'of the. dop is immerse in the liquid, and it further comprises .a'

burner for/directing a thin flame on the dop. The buriier is preferably adapted to be moved with respect to the -d0p supported in the vessel, in such a manner that by said arm for of the grinding and. polishing machine, and

movement the supply of gas to the burner is controlled. The apparatus for setting the stone may have some further special features as will be described hereinafter.

. The accompanying drawing illustrates one embodiment of the invention. In this drawing Figure 1 shows a perspective view Fig. 2 shows a perspective view of the dop holder. Fig. 3 isa similar view of the stone setting apparatus, whereas Fig. 4 represents a cross-sectional view of the device for controlling the supply of gas to *the burner, and Fig. 5 .a simllar view of part of the compressed air reservoir from which the air is led to the burner. perspective'view, partly insection, showing a device for forcing themetal for soldering the stone into the dop, and Fig. 7 illustrates a spherical dop in detail.-

In the arrangement illustrated in Fig. 1

there is the usual lapping wheel or skiv 1 rotatably" mounted on a vertical shaft (not shown). A stationar table 2 has a guide 31h which a suita'by-formed slide 1 is adapted to reciprocate, .a screw 5 serving the purposeof securing said slide in the pro 1 position.

he s ide 4; has a horizontal shaft 6 about which,an. arm 7 is rotatable in a vertical plane which is radial in respect to the skive 1. Said arm 7 is provided with a sliding weight 8 which. can be secured at any desired distance from theshaft 6 by means .of

a screw 9. The said slidin weight conslsts of a number of loose dis s, so that the pressure upon the stone may be regulated y lncreaslng or decreasin the number of disks. Within the end 0 the'arm 7 is a centrally dlsposed recess 11 which is square in cross section and which serves for the resaid bolt having a t the second finger 14. Around said bolt 16 a ception on a correspondingly-formed pin 12 of the dop holder;

The dop holder consists of two fin ers 13,

14:, havingl-near their lower ends oppositely facing sp erical bearing recesses 15. The fin er 13.is integral with-a cross piece, to which the'pin 12 is connected, and to which is hinged the finger 1%. A bolt 16 bears against the exterior face of the finger 13 b means of a shoulder, and extends; throug an elongated slot 18 in this finger, the end of aded connection with Fig. 6 is apressions 22 for the reception of the allo into which the stones are to be soldere I The filling of these holes ma beeffected in the manher illustrated in igs. -6 and 7. In the metal of the ball '21 and opening into the said holes 22 narrow radial slots 23 are made. The alloy in which the stones are to be soldered is made in the form of small cylinders 24 with conical heads, the diame ter of the'cylinders 24 being just av little smaller than the diameter of the holes 22.

For filling the holes 22 the ball 21 is placed upon a suitably formed standard or support- 25, so that the series of holes 22 is located in a vertical plane. A cylinder 24 is then introduced into the hole or depression at the top of the ball, whereupon a suitably formed drift 26 is placed upon the conical head of said cylinder and the latter is forced into the hole by means of a heavy hammerblow on the drift. The relatively soft metal is thereby caused to entirely fill up the hole the slots 23' and immovand is forced into ably secured in the ball.

The arm 7 (Fig. 1) in its polishing posi tion engages a positive stop consisting of a micrometer screw 27 passing through a nut 29 and provided at its free end with an antifriction roller 28. The nut 29, having a scale 36 coacting with an indicating hand 31, is rotatably mounted in a casing 32 integral with the slide 4.

After a bruted or rough out stone has been soldered in each of the holes 22 of the'dop 21 the latter is enga ed between the fingers 13, 14 of the dop ho der, the holder secured to the arm 7, and the latter swung into the polishing position The spherical dop- 21 is then turned by the operative so that one of the stones touches-the skive. The spherical The operation of the device is as follows v shape of the dop and its suspension between F spherical pans permits the' stone to be turned in every direction; the operative is therefore.

only within certain limlts dependent upon the position in which therstone has previously been set by the turner, as hecan adjust the gem in accordance with the grain. The micrometer screw 27 is now turned by means of the nut 29 to such an extent that the antifriction roller 28 nearlyengages the supporting arm 7, when the stone may be ground until the arm 7 engages the, roller 28.

If at such moment the facet has not yet been j ground deep enough, the roller 28 is screwed down'a little so that the arm 7 with the dot 21 can again descend a corresponding distance, 1

and further material may'be ground 011'. .By rotating the'nut 29 the o rative can there forealways limit the depthof the cut, so that it is impossible for the stone to be overground provided the operative uses his normal diligence, and When the operative for some reason 1s obliged to leave his mill the stones need not be taken from the skive.

- When the operative wishes to examine the regress of the work' he may disengage the 30p holder from the machine and examine the stone with a magnifying glass; if the dop after this examination is again mounted in the machine, the stone necessarily reassumes its original position with respect to the lappinggvheel, so that the grinding operation may continued without any further ad i ustment. he sliding weight 8 has for its object to facet on the same stone, such as is usual in present day practice, but he now turns the dop 21 to such an extent that the next stone assumes its proper grinding position, In

this manner the polisher continues his work 55- trunnions the dop 21 may be rotatably' .until one facet has been made on all stones,

after which the dop is taken out of the machine in order that the stones may be adjusted in the proper position for a second facet to be ground, and so on.

With the usual dimensions of the lapping wheel or skive nine grindingmachines'as described may be arranged radially around the wheel. Assuming now that the dop of each machine holdssix stones, and that with each mill one spare. dop is used, it is clear that one polisher can attend to sixty stones without requiring a readjustment of the stones. in the dop, this great number of ,stones does not interfere with the exactness of the grinding and polishing operation, as the micrometer screw 27 always permits of limiting the depth of the cut.

- The dop containing six stones each of which has one of its facets ground and polished is substituted by the spare dop (so' that the grinding operation may becontinued without interruption) and placed in the setting apparatus. This apparatus is illustrated in" Figs. 3, 4 and 5 and -coin rises a 'vessel 33 which is open at its top and as two horizontal pivots or trunnions34, 35, the pivot 34 being fixed, and the pivot 35 forming the end of a screw 36 extending through the wall of-the vessel, so that'the distance between the two, pivots may be increased or decreased as the case may be. Between said mounted in the vessel 33, and forthis purpose the dop 21 'is provided with pans or holes 37. c

The vessel 33 containsa cooling liquid the level of which should be so high that-about pnelaalf of the dop 21 is immersed in the iqui 1 I v Aburner 38 is so arranged that it mayias sume a central position over the'dop 21 so 4 that a flame may be directed upon the dop at a pgint adjoined the top hole 22. The soldering metal in said hole may in thismanner-be melted down' or at least be made so plastic that the stone may be adjusted. By

turning the spherical dop about the pivots 34, 35, all stones may successively be set, during which operation the cooling liquld keeps the dop at a comparatively low temperature.

The combustion gas for the thin flame is supplied through a pipe 39, 40, and the required air is stored in a compressed airreservoir 41, in which the necessary pressureis maintained by meansof a small pump 42 of some known construction, as illustrated imdetail in Fig. 5. Fromthe reservoir 41- the air flows through a pipe 43 to the gaspipe 39, 40-of two-part formation. The bottom part 39 of said pipe is stationary whereas the-top part 40, supportin thebu-rner38 and aprotecting cap 44, is a apted to rotate in a horizontalv lane with respect to the bottom part 39. he bottom part 39 has a threaded connection with the bottom of a casing 45 (Fig. 4) secured to the lower end of the pipe 40; and on the top of pipe 39 a small plate 46 is secured withinthe casing.

45. The pipe 40 opens into'the casing eccentrically with respect to the mouth of the pipe 39 in such a manner, that on rotation of the pipe 40 with respect to the pipe 39 the mouth of pipe 40 is for the greater part shut off by the said plate 46. Under these circumstances only avery small quantity of gas can flow to tlie burner 38, so that the .To the pipe 40 a magnifying glass is se-v 7 180 in a horizontal plane, the said glassv I assumes" a central position over the dop 21, so that the proper setting of the stone may be observed. A positive, stop 48 serves for limiting the extent of horizontal rotary movement of the said glass 47 when turned for controlling the stone.

The "compressed air reservoir 41 may be partially fi ed with a cooling liquid, and

may be placed in communication with the vessel 33 by means of a pipe 49 opening into said reservoir near its bottom, and provided with'a cook or valve 50, so that by opening the cock or valve 50 liquid from the reservoir 41 may be pressed into the vessel 33 should the level in the latter have sunk due to evaporation.

The compressed reservoir 41 is pro-- vided .with'a safety valve 51 shown in detail in- Fig. 5, and mounted in a sleeve 52 screwed 'into a hole. of the cover of the reservoir 41.

The said'h'ole may be used for filling the reservoir with liquid after the 52 has been unscrewed.

said sleeve i The vessel 33 contains a strainer 53 at some distance'below the supporting device for the dop 21, and a drain'cock 54 near its bottom. A table 55'may be secured to the vessel 33 by means .of a screw 56, and serves for supporting the operatives tools.

I What I claim and desire to secure by Let-' ters Patent is: a

1. In combination with a gem grinding and polishing machine of the type referred to, a spherical dop adapted to hold a plurality of stones, a dop holder comprisin two fingprs hinged together and provide with sp erical pans gated opening in one finger and having a screw connection with the second finger, and a spiral spring located around said bolt and tending to increase the gap between said 2. In combination with a gem grinding and polishing machineof the type referred to, a dop adapted to hold a plurality of stones and rotatably mounted in an arm, a lapping wheel or skive, a stationary support outside the lapping wheel, a pivotal joint between said arm and said support permitting a movement of the said arm In a vertical plane radially disposed with respect to the lapping. wheel, and a positive stop adapted to limit the extent of movement'of the said arm.

3. In combination with a gem grinding and polishing machine'of the type referred to, a dop adapted to hold a plurality of stones and rotatably' mounted in an arm, a

lapping wheel or skive,a stationary support outside the lapping wheelfa pivotal oint between said arm and said support permitting a movement of the said arm in a vertical plane radially. disposed withrespect to the lapping wheel, and a positive .stop vertically adjustable by means of a mlcrometer screw. '4. In a-gem grinding machine, in combi? nation, a rotatable lappin holder, means forsupportm'g said..holder,. g and a spherical dop havin wheel, a dop a plurality of stones mounted in spacedre ation on the ei'iphery thereof mounted in said dop hol er for rotational adjustment therein in all directions.

v 5. In a'gem grindin machine as claimed in claim 4, a dop "hold rated relatively movablemembers an means operable to clam said members upon 0 posite sides .of sai spherical dop to hol the latter in adjusted positions.

6. In a gem grinding machine, in combi nation, a rotatable'lap'pintg wheel, a dop holder having OPPOSItB- ac holder, and a ;dop having a plurality of or the reception of said dop, a bolt passing'through an eloner comprisin sepaing spherical bearing recesses, means for supportm saidv stones mounted in spaced relation on the periphery thereof and having spherical bearing surfaces seated in said bearing recesses.

7. In a gem grinding machine as claimed I v in claim ,6, a dop holder comprising a relatively fixed-member, having one of said recesses formed therein, a relatively movable member having the other recess formed v therein, and means co-acting with said members operable to move the second member toward the first to clamp the bearing surfaces onthe dop-between said bearing repositioned in engagement with said wheel 7 bysaid adjustment of said dop.

9. A spherical dop having a plurality of V recesses in the periphery thereof and means within said recesses for securing a plurality of stones upon the periphery of said dop.

10. A dop having a series of recesses in the peripher thereof and having spherical bearing sur acesat op osite sides thereof, sald series of recesses ying m a plane be- .tweensaid bearing surfaces, and means Within said recesses for securmg'a' plura11ty ofstones'upon'the periphery of said dop.

11. A rotatable dop having acirculan series of recesses lying in a plane perpendlcular'to the axis of rotation of the dop and means within said recesses for securlng a plurality of stones upon the dop.

12. In a gem grinding machine, in combination, a rotatable lap mg wheel, a stationary support, an arm plvoted to said support and having its free endjmovable about said pivot in a vertical plane, toward and from the surface of said wheel, a dop holder" car ried by the free end of said arm, a dop carried by said holder, and means for 11mitin the movement-of said arm toward the sur ace of the lapping wheel.

13. A gem grinding machine as-claimed in claim 12, wherein said limiting means comprises a sleeve rotatable upon saidsupport but held from axial movement, and a member screw-threaded within said sleeve and having itsouter end positioned to enga e said arm.

n testimony whereof I have afiixed'iny I signature in presence of two witnesses.

. 7 ARNO BOERNER.- v vWitnesses:

PLAUroFmURE, H. VUHAGRE. 

